It is known that an organic polymer containing at least one reactive silicon group in a molecule is crosslinked by the formation of a siloxane bond, which is accompanied by hydrolysis and the like of a silyl group due to moisture and the like even at room temperature, to give a rubbery cured product.
As an organic polymer having such reactive silicon group (hydrolyzable silyl group), an organic polymer having a polyoxyalkylene polymer, a polyisobutylene polymer or a poly(meth)acrylate-based polymer as a main chain skeleton has already been industrially produced and widely used for applications such as sealing material, adhesive, paint and the like. Particularly, an organic polymer containing a reactive silicon group (hydrolyzable silyl group) is widely used in the fields of sealing material, adhesive and the like, since it shows good workability, adhesiveness, extensibility and the like. However, its adhesiveness to low polar substrates such as polyethylene, polypropylene and the like, and porous substrates such as concrete, wood and the like, and the like is not sufficient, and a further improvement is desired. Particularly, in the field of woodworking adhesive, since conventionally-used urethane-based adhesives contain an isocyanate group that possibly exerts an adverse influence on the human body, there is a strong demand for substitution with an environmentally compatible material, and there are also unsatisfactory levels of water-resistant adhesiveness.
While patent document 1 reports that a cured product superior in the strength and water-resistant adhesiveness is afforded by the use of a curable composition containing an organic polymer containing a reactive silicon group, and an epoxy resin, epoxy resin is feared to exert an adverse influence on the human body and is not a complete environmentally compatible material.